Abstract. Despite large bodies of research examining perceptions of illnesses and perceptions of people who engage in various health behaviors, very little research has examined perceptions of people who have a specific illness. The aims of this research were to create a measure of “patient prototypes,” mental representations of the type of person who has a specific illness, and to examine their associations with other health cognitions and behaviors. Two survey studies (Study 1: N = 208 and Study 2: N = 246) assessed patient prototype favorability for three illnesses (skin cancer, Human papillomavirus (HPV), and type 2 diabetes) as well as constructs from the common-sense model and prototype willingness model. Patient prototypes for the three illnesses were distinct in terms of specific traits and overall favorability. Generally, patient prototype favorability was unrelated to illness representation dimensions in the common-sense model but was positively associated with some constructs in the prototype/willingness model. All three prototypes were positively correlated with perceived vulnerability. The skin cancer prototype was positively correlated with measures of behavioral willingness, behavioral intention, and actual health behavior (UV exposure). Limitations include the use of young adult participants who have relatively little experience with the illnesses examined. Measures of patient prototype favorability and health behaviors need to be further examined and refined. The novel construct of patient prototype favorability provides a foundation for future inquiry into the role that patient perceptions play in health behavior and the implications for the prototype/willingness model and the common-sense model.